As well known, in recent years, along with development of electronic devices and the like, there have been used a wide variety of glass sheets, such as: flat panel displays (FPD), for example, liquid crystal displays, plasma displays, field emission displays (including surface emission displays), and electroluminescence displays; substrates of sensors; covers for semiconductor packages of solid-state imaging devices, laser diodes, and the like; and substrates of thin-film compound solar cells.
Incidentally, for example, in a display apparatus to be used for a television, a personal computer, a smartphone, or the like, when a transparent base material, for example, a glass sheet, having an electrode formed thereon is arranged on the screen in such a manner that the transparent base material is on a user side, there is a risk of occurrence of: a situation in which the electrode is visible to a user; or a phenomenon such as black floating in an image. In order to solve such problem, there is a proposal of blackening the transparent base material side of the electrode (for example, Patent Literature 1).